Experiments with M2 horns.

[Don C]

I thought that this kind of fooling around should have it's own thread and not go into the M2 thread, as these cannot be called M2s.
I mounted the 2452Hs to the horns and set them on top of my PS1400s. It surprised me how much they look like they belong there right off the bat. They look more at home than the PT800s ever did. The compression drivers are resting on an inch of styrofoam, itself resting on the same stand previously used for the PTs. The horns are upside down, so that they don't rock on the rounded part.
My early impression is that they sound breathy, that is, I'm hearing the singer breathe on the mic more than I used to. I like that I can walk around and the sound doesn't change a lot. My listening chair is a little off center in the room, and I'm hearing more from the opposite speaker than I used to. They sound pretty neutral, not as big of a change from the PT800s as I expected. I have a lot of adjustment left to try though.
The crossover is the same JBL SPP-AC1 that I have been using with the PT800. There are no filters left in the woofer cabinets. I Set the crossover frequency to 800, and they sound better to me with the phase invert on. I set the horn eq to 4K, just going by ear. I don't have any protection filter on the tweeters, so I have to be careful. I could live with this setup forever as it is, but those boxes sitting on the chair contain 1500FEs, for future use.
I know that I'm not the only one here who bought these horns, and I want to see what you guys are doing with yours now.

65930

[Don C]

My experience so far is that they sound wonderful on one CD and awful on the next. When they are good, they're very good. Larry Carltons Sapphire Blue CD sounds absolutely amazing. But I'm having some frustration getting the level matched between the horn and woofer. With no padding on the tweeter, the tweeters level control on the crossover is turned down to near it's minimum. Making a tiny rotaion to the level pot makes a huge diference to the sound. Fine adjustment is impossible. I'll get some resistors installed into the driver circuit and continue later this week.

[pos]

Hi Don


My experience so far is that they sound wonderful on one CD and awful on the next.
That is probably a hint that the EQ settings you are using do not give a flat response.

FWIW, here is what it gets to make it flat with the D2 driver:
65945

[Don C]

OK, saying they sounded awful was too much exaggeration. A Steven Wilson concert earlier this month has robbed me of some of my hearing and left me prone to listening fatigue. Tonight, Fleetwood Mac made them sound awesome again.

[ivica]

Hi Don


That is probably a hint that the EQ settings you are using do not give a flat response.

FWIW, here is what it gets to make it flat with the D2 driver:
65945

Hi,

But with 2450H driver, EQ curve would be different, I would expect, especially if Ti-ribbed diaphragm is used, so only after some measurements more realistic EQ can be get, not to mention the bass-to-VHF driver sensitivities differences.

regards
ivica

[pos]

Yes of course, but the horn would still require very specific EQs.
The idea was just to stress the fact that this horn require more complicated EQ settings than say a PT waveguide (ie it is less smooth by nature).

[Don C]

I haven't told the full story about the drivers and diaphragms here, it involves me screwing up. When I saw the horns at Speaker Exchange, I also saw the drivers, 2452H, and brand new at better than half off, looking like a bargain. I suspected that I really wanted 2451s, but looking around, none were for sale, at least not at prices that I wanted to pay. So I got the 2452s. Right after the 2452s were delivered some used 2451s showed up on ebay, pretty cheap. (2451SL-16) I debated with myself for a while and then ended up buying those too.
When I got the adapter plates I knew that they would need to be modified to take both styles of driver. After imposing upon a friend who spent 45 minutes setting up a fixture to mill out the slots, this was done. We set a bit to just kiss the inside diameter of the original holes, then moved it out from center .375, making the slots long enough for a four inch circle. I was sure this was correct. I was wrong. The 2451s need a 4.5 circle, and I'm a bonehead.
So more work is needed but it has to wait.
What I did do, was this. After I listened to the uncoated 8 ohm ti diaphragms for a few hours, I removed them and borrowed the -SL diaphragms from the 51s. They fit right into the 2452s. You just have to move the terminal posts from the old diaphragms to the new ones. These are a big improvement, immediately it was obvious that something had changed for the better. I thought that I would be adjusting the levels up by 3db, to compensate for the impedance change, instead I ended up with 5db more, and they are less harsh even at that level. I'm still fooling with the settings too much though. I set the horn comp down to to 3Khz and have played with the levels endlessly. One CD seems to have too much treble, the next not enough. It's probably a sign that the horn levels are correct and my music selection is the problem. I also have some Truextent diaphragms that 4313B sold me. But I'm not going to install those until I get the resistor network straightened out. And those slots elongated more. And then I'll probably put them into the 2451s.

[Don C]

I may put this Rane equalizer into the system. I'd like to avoid it due to added noise.

65969

[ivica]

I haven't told the full story about the drivers and diaphragms here, it involves me screwing up. When I saw the horns at Speaker Exchange, I also saw the drivers, 2452H, and brand new at better than half off, looking like a bargain. I suspected that I really wanted 2451s, but looking around, none were for sale, at least not at prices that I wanted to pay. So I got the 2452s. Right after the 2452s were delivered some used 2451s showed up on ebay, prety cheap. (2451SL-16) I debated with myself for a while and then ended up buying those too.
When I got the adapter plates I knew that they would need to be modified to take both styles of driver. After imposing upon a friend who spent 45 minutes setting up a fixture to mill out the slots, this was done. We set a bit to just kiss the inside diameter of the original holes, then moved it out from center .375, making the slots long enough for a four inch circle. I was sure this was correct. I was wrong. The 2451s need a 4.5 circle, and I'm a bonehead.
So more work is needed but it has to wait.
What I did do, was this. After I listened to the uncoated 8 ohm ti diaphragms for a few hours, I removed them and borrowed the -SL diaphragms from the 51s. They fit right into the 2452s. You just have to move the terminal posts from the old diaphragms to the new ones. These are a big improvement, immediately it was obvious that something had changed for the better. I thought that I would be adjusting the levels up by 3db, to compensate for the impedance change, instead I ended up with 5db more, and they are less harsh even at that level. I'm still fooling with the settings too much though. I set the horn comp down to to 3Khz and have played with the levels endlessly. It's probably a sign that the horn levels are correct and my music selection is the problem. I also have some Truextent diaphragms that 4313B sold me. But I'm not going to install those until I get the resistor network straightened out. And those slots elongated more. And then I'll probably put them into the 2451s.

Hi,

In such large number of JBL 4-inch drivers 245x, may be a good staring point can be the measurements data that our forum member sebackman
( http://www.audioheritage.org/vbulletin/member.php?600-sebackman ) has shown to us:

http://www.audioheritage.org/vbulletin/showthread.php?36789-Compact-monitor&p=373896&viewfull=1#post373896
http://www.audioheritage.org/vbulletin/showthread.php?36789-Compact-monitor&p=375970&viewfull=1#post375970

regards
ivica

[Mr. Widget]

One CD seems to have too much treble, the next not enough. It's probably a sign that the horn levels are correct and my music selection is the problem.I would agree with pos. I doubt the problem is with the music or the recordings. I bet fine tuning of your EQ is needed. I also doubt you can get there with a graphic EQ. You may want to explore DSP options and good acoustic measurement software.

You've got a great start with these horns and drivers... with further exploration you'll really have something.


Widget

[Don C]

I've been in a somewhat similar situation before. More than once. When the amp in these PS1400s went up in smoke, (:bash:) I added these AC1 crossovers and the Lexicon amps, and started tweaking. It was weeks before I learned to leave the level controls alone and enjoy the sound they were giving me. If you are thouroughly familiar with a system, and then you put on a disc and hear too much bass, you think it's the recording engineer's fault. Right after making a big change to the system, you hear the same change, and think it's you own setup that's wrong. I'm definitely dealing with some of the same thing right now, just on the treble instead of the bass. And I need to mention also that I've had a lot of great sound already from these, when they are good, they're really, really good. I'd never discourage anyone from trying them out.

[Don C]

Here's a surprise, you can still buy useful parts from Radio Shack, like this 8 ohm 20 watt resistor. Parts express only had 10 watt for some reason.
It's probably just my imagination that the speakers sound better today with the pad in place, but that's what I think. The pad is only 6db, so the tweeters are still a few db louder than the woofers. It's nice to make a small level change and only hear a small level change, because the controls are close to the middle of their range now.
And the horns still look good sitting there, I'm constantly admiring the design, upside down or not.

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66008

[Don C]

I've obtained a measurement microphone and set up the REW software to get a visual of what I'm listening to. This is how I had it set up by ear using the few controls available on the crossover and sub equalizer. It seems that I like a lot of bass. I'm looking at some of those fancy DSP crossover/equalizers for the next step. I have quite a way to go on just getting these measurements done right for now. This is just one sweep, smoothed. I'm working on making sweeps with different mic locations and averaging them next. But I had suspected that things that I heard that I didn't like were more of a problem with the woofer than with the tweeters, and this sort of confirms that.

66071

[Don C]

I'll soon be adding a BSS Blu-160 to the system. Bought used from eBay, it was less cost than just buying the interconnect kit from JBL. I'll be using regular XLR cables and regular Phoenix connectors to hook everything up, projected cost less than 50.00
I obviously have a steep learning curve ahead of me.

[Lee in Montreal]

If I remember well, the M2 heavily uses DSPs, so I am not surprised that using an M2 horn might require some time to properly eq it. Then, when it'll look good on a plot, perhaps it will require more time to sound good ;-) I think it would be the ideal set-up for two amps and a digital crossover... ;)

[Don C]

I've started running the software for the BSS in advance of receiving the unit, taking that first step up the learning curve. There are two programs, Audio Architect and London Architect. Both programs can be downloaded, no charge, at the BSS web site. The Audio Architect seems to be newer and it looks like BSS is trying to encourage users to adopt it. There is a zip file available on the JBL pro site for anyone to download, it's the architect file and macro file for the M2 with the Blu-80. I was interested to see what was inside. It's a London file and won't open in Audio Architect. Crap. Worse, when opened in London, the layout is visible but none of the equalizers seem to be doing anything, they all seem to be set to zero. These would probably be adjusted by the tech during installation. The crossovers and maybe more EQ are in a block with no control available, and no visibility of what it is doing. It seems to be what they call a macro, and opens in a separate program called a macro editor. Or I'd hope so anyway, but attempting to open the file in the macro editor shows it to be password protected. Double crap. So you can load the file and it will probably work, but at this point, I don't see any way to make changes without starting over from scratch. So it looks like that's what I'll be doing. Of course at this point in my learning curve it could be that I just don't know what I'm doing and everything I've written here is wrong. We'll see with more experience. That was five hours of frustration that took five minutes to describe here. I'll be starting all over again tomorrow.

66093

[grumpy]

Having been through this with TiDome's 4-way active system it looks like you're off to a good start. Unfortunate the macro is locked, would have made a good baseline.

[Don C]

Yesterday and today's challenge was the secondhand Blu-160. The last person who used it apparently set it so that it would no longer automatically request an IP address on startup, then also apparently did not ever set a fixed IP address into the box either. No connectivity. The solution was to set up an RS232 connetion and use the utility in the help section of London Architect to tell it to use automatic IP address selection again. So the DHCP in a router can work with it. It sounds easy now that I've accomplished it, but it wasn't. I wasted hours trying different computer settings, firewall settings, different network hardware and even different computers.
Here's a hint for anyone who has a similar problem in the future, the London device has to display a valid IP address on it's LCD display after starting up, and 10.1.1.10 and 255.255.255.0 are not good ones, they are telling you that it is not going to work. Stop right there and fix the BSS box.
I didn't even remember when I started that my latest PC doesn't have a serial port. Nor my laptop. RS232 is so passe. I had to find a serial port adapter that plugs in the motherboard and provides an output in a empty slot on the back of the PC. Oh, one more thing, don't forget to record the mac address, found on a tiny sticker on top of the box. Don't ever accidentally rub that sticker off, you need that. Now the box is connected to the network, but the whole weekend, that I had planned on spending working on the sound, is gone. And I still have not even heard this new box yet.
I've switched to using Audio Architect for now, it seems to be a little bit simpler to use. There are no utilities included on the help menu though, so I'm glad both programs exist.
There must be a lot of functions built into that Macro in the factory design, I've added everything I can think of on this new layout, and the CPU meter is still indicating way short of the their design. It's probably a sign that I've missed something.

66111

[grumpy]

"...the London device has to display a valid IP address on it's LCD display after starting up, and 10.1.1.10 and 255.255.255.0..."

you'd have to set your computer to an address of 10.1.1.x (x could be 1). The address won't pass a router but is legitimate. It would be simpler and more convenient to use a 2nd Ethernet device on the computer (so the main connection remains live)... A cheap usb/Ethernet dongle would do.

[Don C]

I was thinking that the 10.1.1.10 address was set by leaving the field blank and letting the firmware provide something by default, but that could be wrong. Maybe it was put there on purpose to facilitate a direct cable connection. I tried to set up a direct cable connection, but that never worked. I think it has to have a crossover cat 5 cable, and I couldn't find one.

[grumpy]

"I think it has to have a crossover cat 5 cable, and I couldn't find one."

Good point... & quite likely if one end isn't auto mdi-x (I'd assume the BSS box is not).

[Don C]

Some progress, but nothing to listen to yet. New cables, cheap ones. And this is how I've modified the horn adapters to accept 2451s. Eventually. The 2452s are back on for now.

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66119

[sebackman]

Hi Don,

I have been using BSS for a few years. They are all DHCP from the box. There is no problem at all to have the BSS units co-exist with you normal network. I have several units in my LAN. I have a BLU800 + BLU BOB in the main system and some BLU16’s.

I will swap in my M2 horns a bit like what you describe as soon as I get some time to build new cabinets.

Probably the previous owner has changed the IP address or the subnet so you cannot see the unit. It is pretty common to change the subnet just to avoid other people on the same net to see the unit.

BSS provides a method to reset to factory settings including DHCP and standard subnet via RS232. If you PM your email I will send the PDF from BSS so you can reset your unit. Something you should do anyway to make sure you do not retain any “leftovers”.

Once on DHCP the unit will show up in London Architect under the “Network” folder at the bottom. Under properties you can change all the network settings to your preferred. In there you can also do FW update very simple. -Very smooth actually.

I suggest setting a fixed IP so you do not have to “chase” the unit each time. However, London Architect, “LA”, will always find the unit if it is on the same network/subnet regardless of settings in the unit or location.

Please also bear in mind no to enable more than one network card in your computer in LA at each time. I don’t know why but enabling more than one can give problems. Use one at a time to avoid problems. If your computer has both wireless and wired cards, only enable one at a time in LA. Both ways works just fine but not at the same time.

Please PM for more info. These units are wonderful and set up right there are few units in the market that can give them a match, I have tried many  .

Kind regards
//RoB

[Don C]

Thank you sir, while I've already fixed my networking problem, I'd still like to read the PDF. I'll PM, and I've cleaned out my inbox for a change.

[Don C]

By opening a new design in Audio architect and then dragging the correct Crown Itech amp into a venue, you can then use the open menu from within the amp setup to load the settings for the M2. Being device files, they don't open from the main menu, you have to have the amp in a design first. It took me a while to figure that out, so I thought I'd share. These files are available from the JblPro website along with the Blu80 file.
But like the Blu80 file, the interesting parts are protecteted by little padlock icons and nothing interesting is visible. So this was not worth the time I spent trying to figure it out.
I've been reading and re-readig , and reading again 4313B's posts of the equalizer and crossover filter data found on page 13 of the long M2 thread, they seem to be exactly what's needed, so Thank you for that sir, if you're following.

[4313B]

By opening a new design in Audio architect and then dragging the correct Crown Itech amp into a venue, you can then use the open menu from within the amp setup to load the settings for the M2. Being device files, they don't open from the main menu, you have to have the amp in a design first. It took me a while to figure that out, so I thought I'd share. These files are available from the JblPro website along with the Blu80 file.
But like the Blu80 file, the interesting parts are protecteted by little padlock icons and nothing interesting is visible. So this was not worth the time I spent trying to figure it out.
I've been reading and re-readig , and reading again 4313B's posts of the equalizer and crossover filter data found on page 13 of the long M2 thread, they seem to be exactly what's needed, so Thank you for that sir, if you're following.You are welcome. I have attached the original version for you to load and look at if you want.

[Don C]

I've installed the BLU-160 and started fooling around with it. It's nice. Here's what the first few measurements look like. The green is the old SPP-AC1 and SPP-SWEQM "by the ear" setup. The red is the settings copied as closely as possible from the I-tech file, (Thanks 4313b!) and the blue is from me fooling with the equalizer settings for a half hour, mostly by turning off filters that don't seem to be helping this setup. The traces can't be compared exactly because I was also moving the microphone around.
The BSS unit cannot exactly duplicate the settings from the Crown amp. The delay is not adjustable in such small steps as Crown provides, and the slope on shelf filters does not have continuous adjustments, instead it starts at 6db and only moves in 3db steps up from there. These are not serious problems. There's lots of tuning left to go, obviously. By ear, the main problem right now is that there's too much high treble, it causes the cymbals to dominate the mix a bit. Looking at the chart, it's not there though. I might get used to it instead of fixing it. The sound is much improved already, as the vocals balance out with the instruments better. It combines spectacular sound and punch with smoothness, it is easier to listen to. This is one of the best setups I've ever heard right now, and I'm not nearly finished with it. The 1501FEs are still in the plan.
I've got to do something about the fan noise of the Blu-unit itself. And rig up a power switch for it.

66157

[4313B]

The 1501FEs are still in the plan.They are fantastic transducers.

I am very glad to hear that you are enjoying this setup. :)

[Don C]

Today I did an exercise in using REW to decide what the EQ settings should be. I started by taking five measurement sweeps from positions spread around the room. The mic was placed in the middle of the room, and moved about a yard left then right then front and back from there. Then I smoothed all of the plots and let REW average them. Then I let REW make an new curve to correct the averaged measurement. And entered that data into the BSS. These new curves are in addition to the curves from JBL, I didn't remove those. Afterwards I took the plots shown here. These are both close to my listening chair, one a foot or two in front of the other. If I had just done one room position and applied the correction without moving the mic at all, I guess I could have could have made a nice flat chart, suitable for advertising.
With this curve the system doesn't sound any better than before I started. Not really bad, but not better either. So maybe today's point is that when you're getting this close to ideal, you can leave it alone. Fortunately, you can save endless different EQ curves, and I'd saved yesterdays, so I just reverted back to the saved values.
The blue is yesterday's measurement. The orange and violet traces are today's data. If I get some free time tomorrow, I might repeat the whole exercise, but bypassing the old JBL curves first, and using less movement of the microphone, keeping it closer to my chair.

66162

[natehansen66]

It doesn't sound better because you're eq'ing room reflections, not the speaker response. Any reason you're not making gated measurements? You really need good data to eq a horn like this.

[Don C]

I understand the idea, that I want to isolate the initial response and separate it from the reflections that arrive later. This doesn't seem to be available in the software that I'm looking at though. Maybe I'm having a simple language issue, I searched the help file for "gated" and found nothing useful. What does REW call this, and what settings work best?

[bubbleboy76]

Here is a link to guidelines how to do gated measurements in REW:
http://www.minidsp.com/applications/acoustic-measurements/loudspeaker-measurements

[Mr. Widget]

A few thoughts on the measurement topic.

Gated measurements (sometimes also called quasi-anechoic) are definitely the way to go at higher frequencies, but unless you can suspend the speaker 10 or more feet from the floor and the other room surfaces including the ceiling are at least that far away from the speaker (meaning a greater than 20' high room) your measurements will only be accurate into the midrange.

For in-room measurements and especially those where you want to compensate for room modes etc. taking multiple measurements in a cloud is really the best technique. I use 8 measurements in a 24" envelope around the sweet spot.


Widget

[Don C]

Today I went through the activities I had planned yesterday. I made some new sweeps, with all EQ curves bypassed to start with. I have the old curves saved as a preset so I can get them back any time I like. One sweep was made from right next to my chair, and two more only a foot forward and back from there. I averaged those and generated EQ filters from the result. REW made 20 filters for me, and I put those into the BSS. This did a good job of flattening out the midrange, but REW didn't even try to flatten out the CD slope down at the top or fix the bass at the bottom. I don't know why. Maybe 20 filters is all it can make. But I made a few high and low shelf filters manually and got it pretty flat. I listened to this for a while and it's not a big change from how it was before I started, which is to say, it's excellent.
I tried making some gated measurements as well. Thanks for linking to the method, Bubbleboy. I had the mic at ear level, and ended up raising it a bit to get the first reflection over 5 ms. I generated filters for that too. The problem I ran into, was that you can't average two or more sweeps to get this filter set, it needs to work from a single sweep. The result doesn't sounds as good to me as what I had before starting, So I reverted. I'll fool with that method more next week. Here's what It looked like with a single sweep next to the chair when I reverted and called it a day. Still a lot of treble there, that can easily be corrected to taste.

66168

[Lee in Montreal]

Since the horns is what can take the most work, then can they be moved outside to avoid reflecftions? Preferably on a grass area. ;-)

Lee

[Don C]

Since the horns is what can take the most work, then can they be moved outside to avoid reflecftions? Preferably on a grass area. ;-)

Lee
This is impractical right now, as I need an audio cable from the PC to the processor, and all of the rest of the system has to be hooked up too. So everything would have to go outside. It would take an hour to get the whole system set up in the back yard, and another to get it back in place in the house afterwards. The Lexicon amps are heavy. Maybe someday in the future. Anyway, my yard is not large, and is surrounded by a tall board fence. Is anyone else even thinking of using 2452s? Seems like it's just me.

[natehansen66]

If you're actually getting 5ms of clean data that should have sufficient resolution to work out everything from the xo up. For a wg like this I'd think a set of polar measurements are needed and then eq is based on consideration of the entire response. I shoot for flat on the listening axis as long as there aren't any other nasties in the front 40-50deg.

Yeah, I think 20 filters is the max on REW. I do my work on the gated data separate from the eq I do at the lp which I restrict to below 300-400hz.

Did you save the gated measurement? It'd be interesting to see the fr and impulse. What was the mic distance?

[Don C]

I didn't post the gated curve because I thought I had probably done something wrong. I could post it. My measurement was made with the microphone about 8 feet away from the speaker. Would closer be better for gated measurements? How close? Pointed right at the speaker?

[natehansen66]

Unless you've got your speaker and mic 7' off the ground and have that distance clear in all directions (including up!) you're not actually getting 5ms of clean data. Just a guess here, but if you have the speaker and mic at 40" off the floor you're only getting 2ms of good data at a distance of 8'! That's a freq resolution of 500hz which is not very good. Here's an article that explains it much better than I can: http://www.hifizine.com/2011/03/refining-a-4-way-open-baffle-speaker-minidsp-2x4/ You can skip down a bit to the part that starts with "A Little Theory"

In my room with 8' ceilings I get the mic and design axis of the speaker at 4' and the best I can do is about 45" from the speaker to the mic. This only gives me a little over 3ms of data. That's ok for 1khz+, but anything below that is heavily smoothed due to the decreased freq resolution. When I want to get serious I drag everything outside, hang the speaker off the back of the deck, and start annoying the neighbors.

I'm curious to see the raw fr and impulse of the M2 wg.

[Don C]

OK, since you asked, here are the gated sweeps from yesterday. Keep in mind that I'm just now learning how to do this, and this probably shouldn't be considered as solid data. I was probably misinterpreting the impulse data, the 6ms bounce may be the back wall, not the floor. This is with all filters in the BSS bypassed. Nobody else has an opinion as to how far away the mic should be placed from the speaker when taking this kind of measurement?

Impulse response:

66183

3Ms gated response:

66184

5Ms Gated response.

66185

[Mr. Widget]

Nobody else has an opinion as to how far away the mic should be placed from the speaker when taking this kind of measurement?
I always use 2m on tweeter axis from a speaker system. If I'm measuring just a single driver I will place the mic 1m from the driver or horn mouth to reduce the impact of floor or ceiling reflections.


Widget

[Don C]

Changing topic for a while, I was dissapointed to hear the BSS at first, not the audio output, but the noise that it's fans make. So I decided to look into disconnecting the fans, as others have apparently done. First, I looked inside. It seems that the brains of this BSS are an Altera Stratix 2 FPGA and two Analog Devices Sharc DSP chips.
The FPGA is from a family introduced over ten years ago, a 70nm process platform. But I guess it's maker must still regard it as a good chip, it seems to still be in production, and is available at Mouser for $460.00 Ouch.
The fans are four Sunon KDE0504pkv3s. I looked them up, and they are specced as some of the quietest 40mm fans available, at 18Dba each. So replacing them with something quieter probably wouldn't help. That's a lot of fans and It doesn't seem to me that the engineers would have put them there if they weren't needed.
I wanted to see where the heat was coming from inside the unit, and used the low tech method of putting my finger on all of the chips and cans. There are air flow dividers inside, the the left two fans cool the left side only, and the right side air is directed to the power supply and main board. The whole left side, where the input and output cards live, seems to be nice and cool. It doesn't make sense to me that those cards have two fans cooling them. So I disconnected those two fans right off the bat, and that works great, half the noise. My theory is that if you had ordered the unit with digital cards over there, you would probably still need those fans.
On the right side of the unit, the DSP chips were very warm to the touch, and the FPGA was hot, so hot that I couldn't leave my finger on top. Ouch again.
I decided not to just disable those two fans on that side. For some reason, these chips don't have heat sinks. Reverting to my old overclocking habits I decided to add some to those three chips. I cut an older Foxconn P3 CPU heatsink into four parts, with the bandsaw. Then I glued them in place on the FPGA and DSP chips. I used Arctic Alumina heat sink epoxy adhesive. It conducts heat well. And those heatsinks are there to stay.
I then disconnected one of the remaining two fans on the right side of the box.
There is a lot less noise with this single fan setup, it's hardly noticeable if you walk away from the rack. Now it's about the same noise level as the satellite DVR that lives in the same rack. I'm looking at adding a foam filter to the remaining fan to further silence it. And now you guys may be wondering if I'm OCD or something, and why can't I just leave anything alone. Well it was bugging me, and now it's not, so to me it was worth the time.

PS, For any fellow OCDs, to open the box you should have a Pozidrive PZ2 screwdriver available, and a 5/32 allen wrench.
(@#$% Pozidrive!)

66186

[ivica]

I didn't post the gated curve because I thought I had probably done something wrong. I could post it. My measurement was made with the microphone about 8 feet away from the speaker. Would closer be better for gated measurements? How close? Pointed right at the speaker?


Hi Don C,

Why not move your speaker with its back-side laying on the floor, and mount your microphone from the ceiling about 1m over the speaker baffle, (if the speaker depth is about 0.5m, then the mic would be at the height of about 1.5 m from the floor) so, for the higher frequency, most of the reflections would come from the ceiling, so delayed about 2m (about 6ms) or more depending on the room ceiling height. Under such situation, a measurement from, say, 400~500Hz and up would be correct, and usable. Then you can move the mic left and right of the horn axis, so off axis measurements can be get. I would suggest you to equalize the response for the 15~20 degs off-axis response as I would believe that would be very near the averaged HF system energy response, or can be a good starting point for work.

regards
ivica

[grumpy]

"And now you guys may be wondering if I'm OCD or something, and why can't I just leave anything alone. Well it was bugging me, and now it's not, so to me it was worth the time."

Nope. It's just funny as I was thinking of doing exactly the same thing (well, maybe thermal grease vs epoxy, but yeah...).
Thanks for being the guinea pig :) ... and documenting it !

[Mr. Widget]

I was thinking of doing exactly the same thing (well, maybe thermal grease vs epoxy, but yeah...).I know what you mean... I also have commitment issues. :D


Widget

[grumpy]

:D

Loaded file in to LA and noticed M2_BaseConfig_BSS is set to run at 48KHz (vs 96).
Was there a rationale stated that I missed (or forgot)? e.g., limited processing resources
or common file that works on lowest common denominator hardware or someone thought
it sounded or measured better? Just curious at this point, as most of my hardware
remains in the 'ordered' state.

[Don C]

I don't know. It's possible that they set it that way so that it will run on a Blu-80, that has the slower 1X DSP. I noticed that the file name at download says Blu-800, but the file is for the Blu-80. They have the ability to change the device type when you load the file.

[grumpy]

That's what I was thinking... setting up the LCR M2 config for 96KHz on a BLU-160 only gets the resource usage meter up to 38%
(no room or user eq)

[natehansen66]

Don - there's something between your mic and the speaker that's corrupting the impulse......there's no clear separation between the first reflection and the speaker pulse. I'd expect the speaker impulse to go to zero in the first couple ms. I doubt the M2 wg is that bad in the time domain.

[Don C]

I pretty much figured that out, since posting those sweeps. To be fair, I did tell you guys that it was probably bad data. And if you look at the first picture I posted on this thread you'll see what was happening. The room still looks just like that. I didn't realize that I needed to pull all of the furniture etc away from the speaker before starting. Don't worry, I'll eventually do this the right way, after I've exhausted every other option. And thanks to everyone who's trying to explain these things to me. I need it.

[Mr. Widget]

Don't worry, I'll eventually do this the right way, after I've exhausted every other option. :applaud:

I remember when I started taking measurements for Project May... my initial measurements were pretty much useless... there is a learning curve.


Widget

[natehansen66]

We all start somewhere! I started by using a radio shack spl meter and "designed" my crossovers with in room, ungated, measurements. I was totally clueless....:banghead:

[Don C]

Today I tried to collect more data, and do a better job than last time. I moved most of the furniture out of the room and put the speaker near the center. I elevated the speaker by putting the woofer on top of another speaker, the putting the horn on top of both. I had about 40 inches to the floor from the base of the horn, and about 8 feet to to the wall that the speaker was facing.
I measured and set the mic 1 meter from the horn throat screen.
here's what it looked like:

66211

66212


The gate was set to 5ms. The red is with no eq applied, the blue is with the standard M2 eq settings, and the green is what I had after manually adjusting the settings for a while. I moved the filter that JBL had set at 3.1 khz, down to 1.7 khz, and removed filters at 9 and 11 khz that were not helping, and made a few other changes I didn't record. The result is more neutral than I had before, but also duller. It needs to have a target curve adjustment to perk it up a bit. My room is pretty dead sounding, intentionally. I have carpet and drapes, and something soft hanging on most of the walls. So it's no surprise that the room response curves down a bit at the top.

[Lee in Montreal]

The diaphragm seems to sufffer from the usual break up at 4kHz. I don't know what is the standard JBL eq, but perhaps you could try a bandpass filter w/ Q= 1.0 (which you can adjust up or down), centered at around 17 o 18Khz with db bump of your choice (most likely around 12db)

[grumpy]

Measured with 2452-SL?

[Don C]

This is what the filters look like now. There are some others in an input filter, but they are small.

66214

Yes, these are 2452H drivers, very recently purchased new, but with used from ebay 16 ohm coated diaphragms installed, because they sound better.

I also fooled with the delay for a while, using a method I've seen described elsewhere in this forum. I set the phase invert on, and adjusted the delay up and down looking for the biggest null at the crossover frequency. Using that method, the best delay for this speaker is zero.

[ivica]

Today I tried to collect more data, and do a better job than last time. I moved most of the furniture out of the room and put the speaker near the center. I elevated the speaker by putting the woofer on top of another speaker, the putting the horn on top of both. I had about 40 inches to the floor from the base of the horn, and about 8 feet to to the wall that the speaker was facing.
I measured and set the mic 1 meter from the horn throat screen.
here's what it looked like:

The gate was set to 5ms. The red is with no eq applied, the blue is with the standard M2 eq settings, and the green is what I had after manually adjusting the settings for a while. I moved the filter that JBL had set at 3.1 khz, down to 1.7 khz, and removed filters at 9 and 11 khz that were not helping, and made a few other changes I didn't record. The result is more neutral than I had before, but also duller. It needs to have a target curve adjustment to perk it up a bit. My room is pretty dead sounding, intentionally. I have carpet and drapes, and something soft hanging on most of the walls. So it's no surprise that the room response curves down a bit at the top.

Hi Don_C,

Interestingly, the shown data about M2 behavior differ much relative to the measurements our forum member RoB
http://www.audioheritage.org/vbulletin/member.php?600-sebackman

has shown us, using 2451Be drivers.
http://www.audioheritage.org/vbulletin/showthread.php?36789-Compact-monitor&p=373896&viewfull=1#post373896

I think that you have to enhance frequencies over 8kHz, as JBL have done

Regards
ivica

[Don C]

I really need to work on a bigger computer screen, and remember to decrease the scale so that I can see the variation better. When I was looking at the green graph on the laptop it looked close enough to perfect that I decided to leave it alone. Later I changed the scale and looked on a desktop PC, and the need for further improvement is pretty obvious. I'm not going to do this again this week though.

[grumpy]

for the few that care: BLU-160 wasn't immediately recognized by London Architect (with laptop ethernet address to same subnet).
I turned off all the windows networking crap except Ipv4 and fixed the device speed to 100M/duplex rather than autonegotiate.
Tools like nmap then found the BLU-box (no crossover cable needed). There's a status web page if you point your browser to the
BLU-box IP address.

Then fired up LArch... bingo. I expect that some of this was power/boot order dependent, but now it works and I can play.
Proper output card and terminal block connectors ordered.
Config I'm setting up should allow for analog -and- digital I/O (4 in, 4 out of each).
Horns are due next week :bouncy:

[Don C]

I was noticing that every time I turned the system on it sounded different from the last time I worked on it. This turned out to be my bad habit of bypassing the filters using the blue buttons along the right side of the eq screen. When I would cycle the power the individual filters would be active again. So it works better to set the gain to zero instead of using the bypass button. It remembers that setting. A firmware bug?

[grumpy]

Do you have the auto "last state save" feature turned on (or whatever it's called).
Sometimes it saves your butt, sometimes it's a pain in the same place.

If I get to it tonight, I'll see if I can replicate the issue/feature.

(ah... you're using Audio Architect ... may be the same behavior as LA, will try).

[Jonas_h]

Changing topic for a while, I was dissapointed to hear the BSS at first, not the audio output, but the noise that it's fans make. So I decided to look into disconnecting the fans, as others have apparently done. First, I looked inside. It seems that the brains of this BSS are an Altera Stratix 2 FPGA and two Analog Devices Sharc DSP chips.
The FPGA is from a family introduced over ten years ago, a 70nm process platform. But I guess it's maker must still regard it as a good chip, it seems to still be in production, and is available at Mouser for $460.00 Ouch.
The fans are four Sunon KDE0504pkv3s. I looked them up, and they are specced as some of the quietest 40mm fans available, at 18Dba each. So replacing them with something quieter probably wouldn't help. That's a lot of fans and It doesn't seem to me that the engineers would have put them there if they weren't needed.
I wanted to see where the heat was coming from inside the unit, and used the low tech method of putting my finger on all of the chips and cans. There are air flow dividers inside, the the left two fans cool the left side only, and the right side air is directed to the power supply and main board. The whole left side, where the input and output cards live, seems to be nice and cool. It doesn't make sense to me that those cards have two fans cooling them. So I disconnected those two fans right off the bat, and that works great, half the noise. My theory is that if you had ordered the unit with digital cards over there, you would probably still need those fans.
On the right side of the unit, the DSP chips were very warm to the touch, and the FPGA was hot, so hot that I couldn't leave my finger on top. Ouch again.
I decided not to just disable those two fans on that side. For some reason, these chips don't have heat sinks. Reverting to my old overclocking habits I decided to add some to those three chips. I cut an older Foxconn P3 CPU heatsink into four parts, with the bandsaw. Then I glued them in place on the FPGA and DSP chips. I used Arctic Alumina heat sink epoxy adhesive. It conducts heat well. And those heatsinks are there to stay.
I then disconnected one of the remaining two fans on the right side of the box.
There is a lot less noise with this single fan setup, it's hardly noticeable if you walk away from the rack. Now it's about the same noise level as the satellite DVR that lives in the same rack. I'm looking at adding a foam filter to the remaining fan to further silence it. And now you guys may be wondering if I'm OCD or something, and why can't I just leave anything alone. Well it was bugging me, and now it's not, so to me it was worth the time.

PS, For any fellow OCDs, to open the box you should have a Pozidrive PZ2 screwdriver available, and a 5/32 allen wrench.
(@#$% Pozidrive!)

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HAve you looked at the temperature difference after doing this modification? When you connect to the BLU, you can read the temperature. I have thought about doing the exact same thing on mine as you have done, but I would be so angry with myself if I ruined it :/ So now my equipment is in another room as the speakers.

[Don C]

Hi Jonas
Please describe the method for showing temperature. The help file doesn't show how.

[Don C]

It might be early to reach this conclusion, but the temperature monitoring seems to be one more feature that works in London Architect, but not in Audio Architect.

[srm51555]

Horns are due next week :bouncy:

I was told more horns are due at the speaker exchange today and Monday, so we are all getting closer.

Also a really big thanks to DonC for his write up on getting a used BSS Blu to connect to the network. I just want to add pushing the locate button after performing the steps mentioned by him and Grumpy made mine appear in the network area of LA. Not sure if it really did anything but after pushing it my BLU100 appeared, so I thought I'd mention it.

Two questions I have are can you look on the BSS unit from LA to verify what is on there and when loading the M2 file as it is will that blow away all other settings. I didn't wipe it clean before I loaded the file because I assumed it didn't need it.

[Don C]

Audio Architect gives you the option to save your Venue file into the BSS unit, and to download it from there also, it's on the file menu. And it asks you if you want to save your file to the unit when you go online. You have to open a file that matches your unit to go online. You can apparently only save one file at a time into a unit, but can have multiple equalizer and crossover presets saved into one file. But the file that is saved into the unit with this method is not necessarily the same file that's running in the unit. You can make changes to the unit on the fly when you are online, and the changes are applied immediately, and are persistent. You can hear this working if you listen and make changes at the same time. But the changes won’t be in the file unless you save them to your disc after making the change, and the changes won't be in the file uploaded to the unit either unless you upload it separately again.
My unit didn't have a file saved into it that could be downloaded. It may be that it was only worked on previously with London Architect, or just that no one ever saved a file to it. I'm not sure how these functions work In London architect, as I'm not using it. The two programs don't seem to be compatible, so you may be better off picking one and sticking with it. For better or worse I'm married to Audio Architect for now, as my file was created in it, and apparently as a result the unit won't go online with London Architect.
I have a long way to go in learning this software myself, and it's probably not wise for me to be instructing anyone at this point, but I'll tell as much as I can.

[srm51555]

Thanks for the reply. I performed the upload using the little green arrow button down by the Network section. is this not the same thing as using "File" then "Save to Device Network"

66303


You can make changes to the unit on the fly when you are online, and the changes are applied immediately, and are persistent. You can hear this working if you listen and make changes at the same time. But the changes won’t be in the file unless you save them to your disc after making the change, and the changes won't be in the file uploaded to the unit either unless you upload it separately again.

I really wish the manual had something more than just pointing to what a RS232 and Ethernet port looks like, because I have no clue on performing the above in LA and have had no luck searching the BSS forums. Is there a place where one can learn more on the real life application side of things? This may just a thing of practice with LA also. Thanks, Scott

[grumpy]

The BSS site has a good introductory training video set for LA. Answered a few questions I had been pondering. I haven't looked for similar AA training, but I expect much of the LA stuff would carry over.

[Mr. Widget]

Here's a basic question... why use one over the other? AA v LA?


Widget

[Don C]

AA seems to be newer and looks like they are actively updating it. It's a little bit prettier and for me, more intuitive to navigate around in. On the negative side, there are no videos yet. AA was the first program that actually worked for me. I could never seem to get London architect to go online, even with the JBL Blu80 file. To be fair, I could have solved it but I stopped trying once I got AA working.
I did find the temperature display in AA. You have to left click on the BLU160 in Room view to highlight it, then right click to find the Default control panel on the menu. I could never find that before because I was going straight to the right click without highlighting first, and that doesn't work. It's tricky.
My internal temperature shows as 53.5 C right now. Seems pretty high. It's sitting right on top of a hot Lexicon NT225 (Really a Bryston 4B-ST) though.

Information From Harman (http://audioarchitect.harmanpro.com/en-US/audio-architect-LondonArchitect)

[Don C]

AA seems to be newer and looks like they are actively updating it. It's a little bit prettier and for me, more intuitive to navigate around in. It was the first program that actually worked for me. I could never seem to get London architect to go online, even with the JBL Blu80 file. To be fair, I could have solved it but I stopped trying once I got AA working.
I did find the temperature display in AA. You have to left click on the BLU160 in Room view to highlight it, then right click to find the Default control panel on the menu. I could never find that before because I was going straight to the right click without highlighting first, and that doesn't work. It's tricky.
My internal temperature shows as 53.5 C right now. Seems pretty high. It's sitting right on top of a hot Lexicon NT225 (Really a Bryston 4B-ST) though.

Information From Harman (http://audioarchitect.harmanpro.com/en-US/audio-architect-LondonArchitect)

Edit: One minute I say there are no videos, the next minute, I find some. (https://www.youtube.com/channel/UC5goGPUXs6EYYEBsFBhQCjA/videos)

[grumpy]

I think Don's right. I was lazy the other way, having already spent significant time with LA
and bringing the system right up. Functionally, for me, there's little difference. I'll probably set up everything in AA once my connectors and output card arrive and I want to start saving my "experiments" :)

(running at 35°C steady state, cpu and memory well below 50% with M2 LCR config)

[4313B]

Edit: One minute I say there are no videos, the next minute, I find some. (https://www.youtube.com/channel/UC5goGPUXs6EYYEBsFBhQCjA/videos)Interesting that all but one were added a mere 22 hours ago.

[grumpy]

OK... couldn't wait as the horns and Klippon-style connectors arrived and had to do -something-
(so this is a little off topic, but related).

Setup LA with factory M2 LCR config but with BLU160 and Digital out
(as those were the cards I was initially dealt ... so to speak). I also have one
Analog in and one Digital in, so -later- there may be some interesting comparisons.

AES/EBU output to MOTU Traveler (used as a 2-ch DAC) and monitored the output via ...
headphones (just a test for throughput and level check). Very clear but obviously
a bit wonky with HF on the left and LF on the right :p ... a quick virtual rewire and config upload
put HF L&R on the headphone monitored channels. Stereo at least. Obviously not tuned
for headphone use so any critical judgement would be pointless, but noticed nothing I
could attribute to the ADDA process or gain problems :). So now, time and a box...

Been thinking about the C34 form factor (chamferred rear corners and angled grill,
but no rear horn loading and much less inset. This thought may pass.

Don, any thoughts beyond a rectangular box?

[Don C]

Look for cards on amazon.com if you decide to swap them.
My idea was to make a more basic clone of the M2 shape, with Walnut veneer. OK just a rectangular box. But actually to make the height whatever the width of a sheet of MDF is. I thought it was always 48, but saw some later that was 49 inches. I wouldn't get as fancy with the baffle as the factory did, just make it flat fronted. It would end up looking like a bigger L200t3. I like the idea of making a two color grille too. Getting fancy with the grille can make up for a plain looking box. JBL had that same idea a long time ago.
I dropped off drawings with a cabinet shop, he said he's real busy, but he'd look at the work and get back. That was two months ago. I liked the looks of the shop though, stacks and stacks of thick sheets of MDF were everywhere I looked, and they had automated machines that looked very accurate. Everybody did look busy there. So I'm still hoping and will bug him again.
For home use or for people who don't listen over the top of a mixing console, something shorter would probably be better, and I may redraw mine. Maybe lower but deeper, maybe even with a slanted baffle.

[Don C]

I created my file from scratch in Audio Architect, and I noticed that the woofer/tweeter channel assignments came out the opposite of what is shown in the JBL provided (LA) Blu-80 file. It didn't bother me, I hadn't placed a singele wire yet when I noticed. I couldn't find a way to fix it in the crossover, it wouldn't let me change the "out" setting on the first filter. But I could have easily crossed the wires anywhere in the design after the crossover to make the two files match. I didn't though, I just wired my system the way it was drawn in AA, and it's fine.

[grumpy]

I was just happy that bringing BLU box configurations up and down caused no
nasty pops or clicks :)

Planning on using 1500AL's on the bottom so I believe a 4+ft3
effective volume for the bass section is what I'm looking at.
Someone has probably posted the M2 bass volume (I'm assuming
it's not the whole box), but I missed the 2216Nd order. I'll get
over it :)

[macaroonie]

Now that you chaps in the land of milk and honey are getting ready to slice up some wood may I take this opportunity to remind you of this interesting-outfit (http://www.aitwood.com/) in Anaheim.
They do pre formed plywood sheets in curves , from memory up to 96" radius.
With a bit of imagination and luck you should be able to emulate the M2 front if that's your fancy.

http://www.aitwood.com/StoreFront.Asp?WoodType=POPLAR&CATID=10&Section=QTRCYL&wDesc=Quarter%20Cylinders%20%2890%20degrees%29

They also have hard maple ply , a new one to me but sounds like it might be good stuff.

Also pre formed MDF components like large radius corners and so on.

Loads of interesting gear , if it was local I'd be down there in a hurry.

M

[srm51555]

Is there a place where one can learn more on the real life application side of things? This may just a thing of practice with LA also. Thanks, Scott

Thanks to Grumpy and DonC for the video idea and link. I eventually found what I needed on page 9 of http://www.bsstechsupport.com/public/appguide/setup-guide-connecting-to-a-soundweb-london-network.pdf I didn't find it at first since I thought it was network connection document only. I also figured out that I need to select Operate and Online in LA to view live sounds. Since I'm running analog and need a high gain signal, Id like to run my cd player straight into the BSS BLU-100 and then use a EC-V to control the volume, essentially eliminating the preamp, any thoughts? Thanks, Scott

[Don C]

I think that you could make the BSS unit into a pre-amp. You would have to study the control panels section of the training, and you might want to add a break in box to get more sources. If you are handy, you could make a volume control for a lot less money than that wall panel, and it could look better too. I'm thinking of adding an external bass level control implemented with a simple pot connected to a control port, and linked to an equalizer gain control. It would duplicate the function of the woofer level controls that I had when I was using a four way active crossed speaker system. I was accustomed to having that control handy to fix up program material that lacks bass, and I miss it.

[grumpy]

Thanks Mac! Been awhile since I've poked at their web site.
They're darn close. Good way to shoot a day, just getting ideas :)

[macaroonie]

Thanks Mac! Been awhile since I've poked at their web site.
They're darn close. Good way to shoot a day, just getting ideas :)

I suppose that's how all those curved sides you see these days start out. It certainly opens up some possibilities to the home builder. Their half round forms could be useable in a 99000 way
Field report and pics obligatory.

Cheers Grumpy

[srm51555]

I think that you could make the BSS unit into a pre-amp. You would have to study the control panels section of the training, and you might want to add a break in box to get more sources. If you are handy, you could make a volume control for a lot less money than that wall panel, and it could look better too.

Thats probably a better idea, cheaper at least. I was hoping I would be able to run the pot over to my chair so I wouldn't have to get up as often. Anyone know the maximum length of wire you can wire a pot in, I think the run would be about 20 feet, if not i'll post the question on the BSS site and repot back. I'll probably also look into wiring a selector switch also since the BLU-100 has 12 inputs.

[Don C]

Sorry about the wall of text below. I've put more time in working on the EQ curves and learning about the process.
By trial and error, and some reading of the help files, I've learned that the REW software is not going to fill in a curve that needs a lot of gain added below the reference level to correct it. It's logic avoids filling in holes, but will do a better job of cutting off any peaks that go above the reference level. So it is not going to give you a big slope up at high frequencies to correct for a CD horn in the system. You will have to make that for yourself before letting REW make it's filter suggestions. It also doesn't seem to like making adjustments too close to the edge of the band you've selected to correct. So you must tell it to start working aa 500 hz, if you want it to start looking effective at 1K. You also have to tell REW not to make filters with more cut than 15db, to match the capabilities of the BSS. REW will make enormous filters boosting the signal and then counteract them with enormous filters in the same area cutting the signal, and the BSS can only do this to 15db max.
So my idea with this latest go-round was to equalize the speakers to as flat as I could get by them adjusting them manually, then to run the REW filter generator afterwards, and see what it gives me.
I hauled a speaker into the back yard for this , connecting them with 50 feet of speaker wire to the amp in its normal location in the house. They were hoisted 40 inches above the ground. I used a 4M USB extender and a second active 4M extender to make the microphone cable reach into the yard. The USB microphone wouldn't work at this distance until I added that active extender.
After driving the neighbors crazy with whooping noises for a while I got them EQ-ed pretty flat at 2 meters distance, straight in front of the speakers and 4.2 Ms gated. The two meters distance seems to be important, making them flat at only 1 meter makes them sound too dull if listening at longer distances. These filters are in the BSS output section. Then I measured a couple of feet off axis in each direction and made an average of these three gated curves. I let REW make an eq curve from that, and used these filters to replace the old JBL provided input section filters in the BSS. Note that the REW suggested curve includes a gentle slope downwards a high frequencies, that I've left in.
If you looked at the first response curve that I posted in this long thread, you notice that my preference is to have a lot of bass. Adjusting the speakers to measure flat on the bottom wasn't doing it for me, I want more. I have them pushed up pretty well at the bottom, we're talking 14db of boost at 20hz. The LE14s can deal with this without any issues at all. I've also put in a notch filter to kill a room mode that shows up at my favorite listening position. This is not new, I'd had something like this adjusted into these speakers by ear, all along. But it was blind, I didn't know the numbers. So the numbers surprised me, I had no idea that I had been listening to a curve like that. But this is what sounds best to me, and I'm keeping it this way.
After setting the speakers back up inside the house, the results are excellent. The treble is back, in a dramatic way. But with a more refined sound than before that is new. I can listen to any CD in my rather large collection and not hear anything that surprises me, except that I'm hearing more resolution and power than I'm used to.
I also got lucky in estate sale shopping this week, and bought 20 plus Audiophile CDs for one and two dollars each. Chesky, Audioquest, Reference Recordings, MFSL, a great find. So I'm listening to them. What I'm hearing is a sound just like what you would hear at a high end audio store or at a good room at the audio show. Maybe better. They image very well, throwing out an enormous sound field. I'm completely happy with this, and I'll be leaving them alone for a while. I'll have to start over of course, when the final cabinets are done, if ever.
I don't know if anyone cares about these response charts, I'm getting a little bored of posting them, they don't really describe the sound well. But here they are anyway, along with the BSS settings that were used to get them.

Output filters on the Horns:

66389

Output filters on the Woofers:

66390

Input Filters, made by REW.

66391

Response curves
Red Curve, the average of three positions curve, outdoors, with only the horn output filters applied.
Blue curve: Also outdoors, after the REW generated input filters were applied. Only one sweep is shown here.
4.2 ms gated.

66392

[1audiohack]

All this work and then taking the time to make sense of it and share it is indeed appreciated.

Thank you for doing it, especially if it is becoming tedious for you. I have been following silently and absorbing as I am sure are others and I thought it was high time to thank you for your efforts to share.

All the best,
Barry.

[Don C]

Dave's True Story: Sex without Bodies, and Dave's True Story: Unauthorized. Chesky Records CDs. Absolutely mesmerizing.

[grumpy]

All this work and then taking the time to make sense of it and share it is indeed appreciated.


+1 :thmbsup:

[Mr. Widget]

Yes, thanks Don! I can appreciate the pain it is to gather the info and post it trying to make it useful for others... I haven't worked on any DIY projects or the like in years, but from work I've done I the past I know what you're getting at.

If I decide to go the BSS route, I will certainly revisit this thread for the useful info it contains.

I haven't dug deeply into it so I may have missed your discussion of the 74Hz notch filter. I find it interesting as I am currently using a similar notch in my room. Mine is at 72Hz set to about -9dB. (Similar room dimensions?)

Also +1 on Dave's True Story! I'll have to check out these albums. I only have their self titled album, but it is quite good.


Widget

[bubbleboy76]

Thanks for sharing Don.

Are the horn output filters taken from the JBL M2 settings?

Which crossover-slope do you use (acoustical and electrical)?

[srm51555]

All this work and then taking the time to make sense of it and share it is indeed appreciated.



+2. Thanks for blazing the trail. I've never posted anything close to your extent, but can imagine it being a time vortex. Hopefully now I can find some 2451's so I can join the fun.

[natehansen66]

Nice work! I do outdoor measurements myself and I can appreciate what a pain in the rear it is. I drag my amps and stuff outside so that's a bit easier than running cables everywhere. To make sure I understand your setup: speaker and mic at 40" off the ground with the mic at 2m (78.74")? Is that 40" the location of the cd exit? That would only give you about 2.5ms of clean impulse for the wg and a bit less for the woofer since it's closer to the ground.....it definitely looks to me like you've got some reflections in your data.

Hopefully I just misunderstood your setup and I'm not the guy raining on your parade :eek:. I generally try to keep the mic distance equal to the distance to the ground to maximize the time with no reflections. A 40" mic distance should get about 3.6ms of clean data which is about what I can get in my living room.

Another method for eq'ing a cd horn is to cut the midrange frequencies where you see gain from the device, rather than boosting hf. In the digital realm it's all the same, but you could probably get away with a little less digital attenuation on the tweeter channel if it's needed.

[Don C]

The crossover data is copied from the file that 4313B posted earlier in this thread. Here's a graphic, from my system, below.
Regarding the height, I remembered the measurement data wrong. I measured again. I had 48 inches not 40. That was to the base of the horn, so it was 55 inches to the center of the driver. I measured 78 inches to the screen in the throat from the tip of the microphone. It's a Stanley tape, I tend to round off to 39 inches to measure meters. Its a bad old habit I guess. There was grass and weeds in front of the speaker on the ground, I wouldn't expect a sharp reflection. Here's the impulse response that I was seeing, you can see the little glitch I saw that made me decide to set the gate at 4.2
The measurement is saved, so I can re-plot the data at any gate time I like.

66399

66400

[Aaron]

For my system, I had to set my limiter thresholds to zero to avoid compression, how about you?

[Don C]

I'm not noticing any compression, but I'd love to bypass those limiters anyway.

[natehansen66]

The crossover data is copied from the file that 4313B posted earlier in this thread. Here's a graphic, from my system, below.
Regarding the height, I remembered the measurement data wrong. I measured again. I had 48 inches not 40. That was to the base of the horn, so it was 55 inches to the center of the driver. I measured 78 inches to the screen in the throat from the tip of the microphone. It's a Stanley tape, I tend to round off to 39 inches to measure meters. Its a bad old habit I guess. There was grass and weeds in front of the speaker on the ground, I wouldn't expect a sharp reflection. Here's the impulse response that I was seeing, you can see the little glitch I saw that made me decide to set the gate at 4.2
The measurement is saved, so I can re-plot the data at any gate time I like.


Ok, that makes more sense.

[Aaron]

Don, could you give your best guess as to the size of the heat sinks you put in your BLU box?

[Don C]

25mm square.

[srm51555]

Hi Don,

Any updates on your project.

Thanks,
Scott

[Don C]

They sound great with the horns just sitting there on the PS1400s, so my motivation to build the bigger cabinets is weak. I'm busy with other things. I'm playing them almost every day though. For those who are disappointed that they can't obtain the D2 drivers, these 2452s with the coated diaphragms sound pretty amazing to me. The 2452s were still shown as available at Speaker Exchange for less than 400 brand new in the box, last time I looked. Add 179 each to replace the diaphragms with the aquaplas coated ones and you are in business. OK it's still not really cheap, but this stuff was far more expensive just a couple of years ago, and who knows how long the fire sale will last.

[sebackman]

Don,

Turn the limiter to +20 db and they are automatically turned off.

By the way, JBL states 36db LR filters and in our BLU units there are only NTM36. Does anyone know how close that is to LR36?


Kind regards
//RoB

[pos]

They are probably building the LR 36db/oct by chaining two Butt 18dB/oct

[Don C]

All I know is what BSS tells us. It sounds like they make it from two filters in series, but with slightly different frequencies.
LINK

73385 (http://www2.bssaudio.com/product_downloads/PDF/NTMFilters.pdf)

[Don C]

I'm trying to visualize M2 components in a 4365 sized box here.


Edit: Getting fussy with the drawing.

[zeljkor]

http://sound.whsites.net/articles/ntm-xover.htm


All I know is what BSS tells us. It sounds like they make it from two filters in series, but with slightly different frequencies.
LINK

73385 (http://www2.bssaudio.com/product_downloads/PDF/NTMFilters.pdf)

[Don C]

Thanks for that, it's a good article.

[srm51555]

I'm trying to visualize M2 components in a 4365 sized box here.


Edit: Getting fussy with the drawing.

Great to see your getting started on your project. The original M2 cabinets are quite large in height so they might not fit well with a living room decore, I would be hesitant with them and the kids in mine but they do raise the 2216nd off the floor nicely.

keep us posted,
Scott

[Don C]

I started wondering about the size. So I did some CAD (cardboard assisted design) work and mocked up the cabinet. It was too big for my room. And probably too big for me to ever move. I have never seen 4365s in person, and so I didn't know how huge those are. They are huge. So I've redesigned my cabinets smaller.

75434

[DES-1]

I started wondering about the size...




Be careful, there must be a point where reduced volume and baffle size will begin to cripple performance, despite flexible tuning of dsp. I've been thinking along the lines of a 4367 enclosure but it is nearly as huge, roughly 37x22x17.

[Don C]

I'm looking at:
38in x 21in x 13 in for 4.35CF.
So it's still pretty big.

[bubbleboy76]

I have never seen 4365s in person, and so I didn't know how huge those are. They are huge.

My wife could have told you that! She almost had a heart attack when we got ours :)

[ivica]

http://sound.whsites.net/articles/ntm-xover.htm

Hi zeljkor,

Very interesting link, and thank You it.
I wonder what would be the differences betwenn NTM and "standard" LR crossover (say 4th order) from the listener point of view, not to mention its complexity (including additional noise and distortion "contributions " in the signal path, if realized in analog domain ).

I want to emphasize here that even " brick wall " filters are not so "wellcome " as audio crossover filter in the multi way' speaker system when the driver are appart each the others.

Mybe here in M2 solution sharp LF cutoff is a must to protect D2430K driver diphragm from the "over- excursion " at lowe frequency, as M2 horn loading under say 1kHz is not so perfect.

Regards
Ivica

[ivica]

.....I did some CAD (cardboard assisted design) work ......

75434

HI DON C,

What a nice definition!

But in order to get sound monitor bass response small box is not appropriate solution.
Electronic LF EQ can be applied on many other solutions, but its sound is far from being compared with the "natural" driver response.It would be nice if we can get pancake like bass box solution, preferably postcard size, so can be hanged on the wall.

I do not want to mention here some military developed ultra LF very narrow bass-band
DSP controlled multi elements array solution, that can deliver over 140dB sound levels.
I have no idea about THD and FR response in the pass band of such sound sources.
http://www.explainthatstuff.com/directional-loudspeakers.html
https://www.google.com/patents/us7343017 (http://www.explainthatstuff.com/directional-loudspeakers.html)



Ivica

[Don C]

The box dimensions are set now. But I think that a grille cloth is badly needed. And there is still a decision left to make about the style and color. I'm leaning towards two tone, because three feet of plain black seems like a lot.

75663 75664

75665 75666

[pos]

Are you going to raise them on feet?
The center of the woofer is around 60cm off the floor in the original design.

[sebackman]

Some inspiration.

75669

[Don C]

I certainly will experiment with placement and height. For some reason the existing le14h-3 woofer sounds great, even though it and its vents are right down next to the floor.

[Don C]

My wife gets a vote, and in this case I think it's the deciding one. For this:

75680

[Don C]

It's about time to be converting ideas into cabinets. This is going to lack some of the precision that we've seen on some other recent projects. I'd like to call this a garage project, but my garage is too full of other stuff, so I have to wait for nice days and work in the driveway. I started with 3 sheets of 1 inch mdf. Special order. Because the full sheets are too large and heavy to manage, I asked the lumber yard to cut each sheet into four equal sized pieces, much easier to deal with. They do this with a big panel saw, but unfortunately, that saw doesn't cut square.
I don't have pictures of the cutting, but I took the sheets to a friend's house because he has much nicer equipment than I do. We worked on trimming the parts square on the table saw, then cut them to size, then cut rabbets. I'm pleased with the results. You might notice that the fit isn't perfect, it's mainly because the thickness of the sheets varies. From a low of about 1.03 to a max of about 1.08. I think that it will work out OK, the back is not very important to me, and I'll try to fix up the fronts. The fronts will eventually be covered up with cloth and molding anyway. After cutting it was on to saw horses in the driveway for test fit, then glue and assembly. The resulting cabinets are just barely manageable. By the time I add the backs and bracing I'll probably have to move them around on a moving dolly. The schedule for the next sunny day that I have free includes speaker holes, internal bracing, and backs for the boxes. Patience is needed, It might be a few weeks until the next update.

76007

76008

76009

76010

[srm51555]

Hey Don,

Nice progress, thanks for the update.

[JeffW]

What are the big blue/aluminum bar clamps?

[Flodstroem]

Nice job Don and my own project will be very similar...... :blink:


What are the big blue/aluminum bar clamps?

yea, looks to be very helpful those clamps. Should maybe invest in a couple of pairs......... :p

[Don C]

Those are bar clamps from Harbor Freight tools. I like the rectangular channel design. It allows them to remain standing upright while assembling the speaker on top of them. By the way, that was just the first mock up. I decided to move the clamps right out to the corners of the boxes before clamping with glue.
http://www.harborfreight.com/60-in-aluminum-f-style-bar-clamp-60673.html

What are the big blue/aluminum bar clamps?

[JuniorJBL]

Coming along very nicely Don!!

Thanks for documenting the whole process!

How tough is it to get the bolts or nuts (which ever you chose) under the M2 mounting ring for the 2452?

Thanks again! :)

[Don C]

Installing the larger compression driver is not easy. JBL intended for the horn to be used with the smaller size D2 and that allows them to assemble the plate to the driver first, then the plate to the horn. We can't do that with the larger drivers.
You will want to choose 1/4-20 X 1 inch long set screws to go into the compression driver, and regular 1/4 inch nuts to fasten to the plate. The space between the plate and the horn is tight, but the parts can be assembled with some patience. I had to use my pinky fingers to start the nuts. I worked with the driver on the bottom and the horn on top, sitting at the edge of a table. I used the tip of a flat a screwdriver to hold the two parts slightly separated to get all 4 nuts started. After struggling with the method for 15 or 20 minutes on the first horn, the second one went right together in only a couple of minutes of work. The #10-14 x 1.5 inch plastite screws worked perfectly on the horn to plate assembly.

[JuniorJBL]

Yes that is kind of what I gathered from the looks of things. I am thinking the 2451 will be a tiny bit easier than the smaller bolt pattern but not much. Just a wee bit more room for the fingers.

[Don C]

I'll catch the group up on my progress. I have plenty of photos.

Here I'm gluing a sheet of MDF to the baffle to make it thicker. Due to memory failure I selected the wrong thickness, it's only 1/4 inch, and it should have been thicker. I'll just leave it as is. It stops well short of the edge of the baffle to leave room for the grille cloth frame and a decorative molding. In various photos you can see that I'm adding wood filler wherever the surfaces aren't quite flush, I tend to build it up too high on purpose, and it will be sanded down flush later. This is all going to be hidden later anyway.


76340

Here I have drilled the holes and made the cutout for the horn and I'm test fitting it. You can see some plastic templates that I made for this task in the last picture, but they didn't transfer the pattern well. I would have been better off to just lay the pattern out in pencil and drill. That's what I did on the other speaker and it came out better. But it's not really a problem, I just ovalled the holes a bit as needed to make it fit.



76341

Here I'm looking at the woofer and port layout, with a template.

76342

[Don C]

Next was the holes for the woofer. This was my first time trying out this Jasper circle jig. Drill a 1/8 inch hole in the center. Set the circle jig to 15.25, plunge to 5/16, and start cutting. Reduce the circle size by a half inch and repeat. After getting down to 13.75, plunge all the way down to 1 inch and cut again. Then set the plunge deep enough to cut all the way through, and cut all but an inch in two opposite locations. I didn't want to finish the hole with the router because the jig is fixed to the center, and you don't want the router going off center or falling through when it cuts the last bit. I finished the holes with the sabre saw. I found this to be a fun part of the build, and not too difficult.

76343

76344

76345

[Don C]

I also used the jig to make some collars. I started with the inner diameter set to the same as the outside dimensions of the cardboard port tube. Then increase the size by 1 1/2 inches and cut again to make the collar. You have to make sure that you have scrap wood underneath, and make sure that the center pin goes all the way through into the scrap. Even doing that, some of the collars came out eccentric, they wouldn't do if the outer circle was important, but for this, its not. These will be glued to the back of the baffle. They should make it easy to experiment with different port lengths. Just a small dab of RTV will hold the tube into the collar, and if I want to cut the tube it should twist free easily. And with the port tube installed flush to the back of the baffle instead of to the front of the baffle, I can use the roundoff bit on the router to flare the port hole in the front.

76346

I made some more collars a little bit fancier. I set the diameter to the same as the outside of the port tube, then set the plunge to cut to half the board thickness. Cut the circle. Then set the diameter to the same as the inside of the port tube, plunge to full thickness and cut again. A stepped circle. Then cut the outside circle the same as the other collars. I smoothed the inside with a flush trimming roundoff bit, and voila. Port tube flares, home made.

76347

76348

[Don C]

Cutting out some rectangles for the inside cabinet braces. I wanted the inside holes to have rounded corners so I used a hole saw to make them, and finished the cutouts with the sabre saw.

76349

76350

Putting in the hurricane nuts for the woofer mounting. I used a C-clamp to press them in from behind.

76351

Gluing the inner braces in place.

76352

[Don C]

Starting out on building the back of the cabinet. It has to have a removable panel so that I can install and remove the horn easily. I started with a little strip at the top. Then added a cleat that goes underneath to support the removable section.
Then another cleat. It fits against the cabinet brace. The lower section of the back will be glued so that half of this cleat is showing.

76353

76354

76355

Here I'm gluing those collars in place on the back of the baffle. I used a short section of port tube to center the collar, clamped with glue, then removed the port before it got stuck.

76356

[Don C]

Another mock up, this time with the woofer added.

76357

Last photo for now. It's not finished until it looks as good as this.

76358

[RedCoat23]

Great work Don :)

Love the mdf flares. I had to cut stepped ports in my B460 clone so the plastic didn't show through on the edge of the cabinet, but I didn't do the extras step of rounding - very cool :bouncy:

[srm51555]

Nice work my friend. Good job on the pictures, they are a pain in the rear during the build but appreciated by many after the build.

[badman]

The hurricane nuts are horrendous if they work loose- I suggest (since they're already installed) putting a small screw (with glue on the threads to really lock it down) with the head securing the flat section of the hurricane nut- that will prevent it from working loose of the MDF when you're removing driver mounting screws. The issue with both those and T-nuts is that you're usually pushing the driver into the screw head when removing to ensure the driver doesn't slip or lose contact with the phillips/hex/whatever. That pressure along with the wiggling from the screw rotation is sometimes enough to push hurricane or t-nuts out from the MDF, and then you're in a tough spot for getting the screw free of the cab.

[SteveJewels]

Very nice work and great documentation!!!

[Don C]

There's a little progress to show. I added another internal brace under the woofer and a smaller one at the top of the cabinet. I added some cleats along the sides of the opening at the back and glued the lower part of the back on. I cut the terminal plate opening. Now the cabinets weigh 79 pounds each. I think that the veneer is going to be next. I'm reading up on the topic.

76411

76412

[4313B]

Exciting! :)

[Mr. Widget]

Looking very nice!
I apologize for the question, as I'm sure this was covered, but in a nutshell how do your cabinets differ from stock?


Widget

[srm51555]

Looking good Don.

[Don C]

Looking very nice!
I apologize for the question, as I'm sure this was covered, but in a nutshell how do your cabinets differ from stock?


Widget

I don't have a recording console in my living room, so I don't need such a big tall speaker with the horn looking over the top. These are smaller and fit my preferences better. They should also be prettier, with walnut veneer and grille cloth, but that's hopeful speculation at this point.
My earliest drawings were kind of plain and ugly. Looking too much like a Cornwall. So I wanted to add something to the front. Also , I was thinking about cloning the 4365 but with the M2 horn. That turned out to be too large once I made a mock-up. I started over. I increased the width over the JBL design until I had enough room on the baffle for grille cloth frames and some inch wide walnut moldings on the front. I set the height as tall as I thought I could stand to look at and, and set the depth to a 1.6 ratio to the width. I checked the volume, saw that it was bigger than 4CF, and decided that that was good enough. So that's what I'm building. Looking back, it wasn't very scientific.

[Mr. Widget]

Thanks Don.

I agreed 100% on the aesthetics. I find the tall black coffin look of the Factory M2s a show stopper for me.
I would be concerned that changing the dimensions may affect performance. I'm not saying that your changes will affect performance, but I would want to compare the two side by side, before I committed.

I also agree, that your proportions look much nicer.

Keep up the great work and continue to keep us posted.


Widget

[Don C]

More work to show. I started today by trying to fix a problem that I had created for myself earlier. I made the sheet on the baffle too large, because I hadn't decided the port locations at the time I cut it. So set up a fence for the router and milled some of it away. It will allow more flat surface to veneer and leave uncovered at the bottom of the speaker. With some wood chisel clean up and sanding the job came out OK.

76439

76440


Time for my first ever try at veneering. The veneer had been stored for years, was curled up badly, and and I had to figure out how to flatten it. I tried laying it flat between boards for a few days and it curled right back up again as soon as I removed the boards. I ended up ironing it with a steam iron, that actually worked well.

I laid the sheets of veneer down on some shelving material and cut it from the roll with a utility knife. The shelving material is sacrificed, its surface gets cut up. I made every veneer piece 1 inch oversized. That turned out to be a mistake, as the veneer trimmer works better if there is not a lot of extra material hanging over the edge.

76441

Here I put some glue on the cabinet and spread it out with a roller. I'm using regular wood glue. My thinking here is that I want the surface to be hard so I didn't want to use the softer contact cement under the veneer. I'm hoping that this method turns out more durable. Time will tell.
I used a foam paint roller to spread it out. It worked OK, but is kind of wasteful, as a lot of the glue goes down the drain when you clean that roller.

76442

I rolled the veneer with a rubber roller to press it down.

76443

[Don C]

Then I laid a towel flat on the veneer, put some boards on top, and clamped it all together. I let the glue dry, then took the clamps of and started working on the edges.

76444

This wood glue method is unforgiving. Most of my corners are not as square as I would have liked them, where the filler is sanded. The filler is a little bit softer than the MDF, and so it doesn't quite sand down flat. This causes the glue to fail to stick near the ends. I almost changed methods to use contact cement there, but I went back and fixed one loose end by squirting more glue underneath and clamping that end again. The repair there worked perfectly, so I continued with the wood glue.

76445

76446

I had to use some shears to cut off most of the excess material. Then switched to the edge trimmer to cut the veneer flush with the edge. I could have skipped a step here if I'd followed instructions and cut the material smaller. The shears worked fine though.

76447

I'm happy with the result.

76448

Last one for now. Moldings and paint are next.

[pos]

Very nice!
I can't wait to see how they look like in their final state!

[Mr. Widget]

Time for my first ever try at veneering. Congratulations! You pulled it off! Thanks for the excellent documentation.


Widget

[grumpy]

Like the veneer orientation (looks "grounded"). Appreciate the process documenting!

[bldozier]

Marked it cause I enjoyed your write up.
You used which glue. I read tightbond is heat
activated as well, II having a higher working temp
the I, iirc.
Interested to know why you did not heatlock
your veneer. Non paper backed?

I have my first veneer come up, as well 10 or 20mil
paper walnut😜, however it was contact or heat lock

no more hardware store they just went outta business
so, just trying to prepare before I purchase...

[Don C]

I have seen veneer with heat activated adhesive on the back and I think that it is probably good stuff. If I ever do this again maybe I'll try that kind. But this is just plain paper backed, with no adhesive until the user puts it on. It was cheap on eBay. The wood glue is Titebond 3, just because I ran low on the Titebond 2 that I started with. These glues don't need any heat to set.

[JeffW]

I have seen veneer with heat activated adhesive on the back and I think that it is probably good stuff. If I ever do this again maybe I'll try that kind. But this is just plain paper backed, with no adhesive until the user puts it on. It was cheap on eBay. The wood glue is Titebond 3, just because I ran low on the Titebond 2 that I started with. These glues don't need any heat to set.

Titebond doesn't need heat, but it's pretty neat to use it that way. You put a couple of light coats of Titebond on the substrate and the (regular paper backed) veneer, let them dry completely. Then you can place the veneer onto the substrate - dry glue to dry glue - and use an iron (with a protective tee shirt or something over the face of the iron) to adhere it. Works like heat activated contact cement.

So when people talk about ironing down Titebond, this is what they are referring to.

[srm51555]

Congratulations! You pulled it off! Thanks for the excellent documentation.


Widget
Looking good Don. There is some really good information in the beginning of this thread also.

[Don C]

This weeks update. I had to get the back finished before moving to the front, because it won't be so simple to lay them down with the back up once the moldings are on the front. I did a test fit on the removable panel, and that was fine until I tried to remove it, and found that it was too tigt of a fit, and it didn't want to come out. It was OK, because I could stand it up and push it back out from the front. Of course that won't work later once the horns are installed. I needed to enlarge the opening a little bit. And I decided I need a handle. I routed out a hole half way through, then moved in a quarter inch in height, and routed all the way through. Those pencil lines are where I clamped boards to fence in the router, for the horizontal cuts. I ended up freehanding the vertical cuts, then cleaned up the holes a bit with a wood chisel. The wide part goes on the inside, to make the place to grip. I need to glue a piece of wood inside to close up the hole, but it's a no cost method to add a handle.

76491

Then I laid out and drilled holes to fasten that back section and put in hurricane nuts. I want a little overboard with the number of screws. Half this number might be enough.

76492

On to the front. I added the moldings along the edges of the front. These are just made from walnut boards cut to size on the table saw. Then the fronts were sawed at a slight angle. This is supposed to match the curvature of the horn at the edge. It should minimize any diffraction there, the grill frame will match the same profile. It wasn't easy to install these, the boards weren't very flat or straight when I started with them, and so the resulting moldings are not very flat or straight either. But with some struggle, they are securely glued into place, with some variation from flush along the sides. I may round the edges on these, they are sharp for now.

76493

I made the length the same as the plan for the outside dimension of the grille cloth frames.

76494

Next was a strip of veneer that covers the bottom where the grille cloth ends. You can see here that I wanted to toughen up the bottom of the cabinets as I'm not veneering there. I painted it with a thin coat of wood glue.

76495

[Don C]

Then it was time for masking tape and paper.

76498

Then black paint. This is semi-gloss Rustoleum from home depot. The label says you don't need primer with this. Its not as good as the Krylon, the finish gloss varies a lot across the surface. Much of it will be hidden behind the horn anyway, and the rest will be behind the grille almost always. They are starting to look a lot like the artwork, quite a transformation.

76499

Next up, maybe the hardest part, grille cloth frames. I'm not too worried though, the advantage of working on them, they are loose parts, and it's not too much trouble to throw them away and start over if the plan doesn't work out.
Then lots of small jobs, wiring, fiberglass, light sanding, Watco danish oil, maybe some feet, etc.

[JeffW]

Getting close now for sure, can't wait to see them finished.

How are you going to mount the grills?

[Don C]

At the top of the plastic horn there is a reverse 45 degree angle molded in. I'll show pictures later. I will cut a wedge of wood there to match that angle, and glue it to the inside of the frame. The frame should just hang nicely there with the wedge and gravity pulling the frame flat to the baffle. At the bottom I can just mill a small recess in the frame to accept some Velcro. Or I could get fancy and glue a magnet or two there.
Edit: Pictures added

76510

76511

[Don C]

Here's the last set of updates for now, as I'm pretty much finished.

Picking up from where I left off before, I started cutting out parts for the grille frame. I cut curved bows for the front by tracing the correct line from the front of a horn. Then I cut the parts out on the band saw, leaving a little extra material. I had to borrow that saw because I don't own one. I clamped several of the bows together and sanded them on the belt sander to get the profiles exactly the same and right to the lines. All of the wood is all about 7/16 of an inch thick. I allowed about a half inch for the grilles in the design, with extra room left for the thickness of the cloth. This is probably not enough thickness for a good robust design. Oak was used for the side rails, because I happened to have some. I think that the wood for the top and bottom bow sections is Douglas Fir. Again, I happened to have some. The front of the side rails is cut at the same angle as the moldings. 8.5 degrees from square.

76588

76589



I made rabbet joints at the corners to maximize the glue surface area. I clamped everything together on the table and glued them up. I used two bows stacked and glued together at the bottom. The center bow is made of 3/4 inch plywood for more strength. It's smaller front to back because it has to sit on top of the higher baffle section. There wasn't room for that at the top, but that's where piece that goes behind the front edge of the horn is located. The wood there is angled at the bottom to match the profile of the plastic behind the top of the horn. During test fitting I trimmed that area with a wood chisel until the frames sat at the right height, flush with the top of the cabinet, after the cloth was considered.

76590

76591

[Don C]

After test fitting the assemblies to the speaker I decided that they were to flimsy. I added some reinforcement along the sides of the woofers to provide more strength. The shape looks funny because I used the wood scraps left over from cutting the bows. I had to trim aound the port openings. The frame is strong enough now, but only if I am careful handling it. I painted the finished frames with flat black primer. It looks a lot better than the semi-gloss Rustoleum does, I should have used this for the baffles.

76592

76593

I epoxied magnets to the back of the grille frame to hold the bottom of the frame, and put a screw into the matching location of the baffle to hold the magnet. You can adjust the amount of grab from the magnets by turning the screw. All of that was proven un-necessary later on.
This mounting scheme looks right, but it has occurred to me that if anyone but me ever removes the grilles, they will probably break them. You have to pull out at the bottom just a little, then lift. Pulling out the bottom more than a couple of inches would instantly break these frames. Lets hope that never happens.

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[Don C]

After the frames were ready, I started on the cloth. This tan cloth is from Huntley audio. It arrived in the mail with a few snags already in the cloth. I don't think that they will show up in the photos, and you cant see it in person from more than a few feet away. Still, Huntley loses my recommendation here.
I copied the the installation method exactly from this older thread here. So I'm not going to repeat everything.
http://www.audioheritage.org/vbulletin/showthread.php?26984-Grille-Cloth-Installation (http://www.audioheritage.org/vbulletin/showthread.php?26984-Grille-Cloth-Installationhttp://www.audioheritage.org/vbulletin/showthread.php?26984-Grille-Cloth-Installation)

As per the instructions there I used a hot iron on dried Weldwood contact cement. This method works great.
The installation looks good. I keep having second thoughts about this color though. The finished grille assembly fits into place with a tight friction fit between the moldings. No catches or magnets are really needed. It's just right.

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[Don C]

Then it was time to start finishing the wood. I sanded lightly with 220 grit on the orbital sander. I managed not to sand through the wood anywhere. I then applied the Watco Danish oil finish. This is medium Walnut. It's oil mixed with stain. The oil dries after a while, leaving a wax finish behind. I applied it with a paintbrush then buffed it off with clean cloth. I'm happy with the result. The stain shows that there are a few spots where I was careless and allowed glue residue to remain on the wood for too long, mostly on and near the sides of the moldings. It shows up as light spots. I'll try to touch these up later.

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[Don C]

After admiring that work for a while, I installed the fiberglass. It's Johns Manville B777. I ended up using five packages of this. Five dollars a roll at the local home improvement store. Half of what I bought is white, the rest brown. It seems to be the same stuff regardless of the color. I used 3M spray adhesive to stick it to the walls. Afterwards I sprayed the fiberglass lightly with Deft clear finish to cut down on the shedding.

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Then the ports went in. These are just fastened into the collars with two small dabs of RTV, in case I want to alter the tuning. The ports are 10 inches long counting the baffle thickness. That should give me about 26 HZ port tuning. Initial listening shows this to be fine. I'll probably go back later and glue these with lots more RTV.

I put the tweeter protection networks on the rib of the middle cabinet brace. Both drivers are wired with Monster XP 14 gauge.

[Don C]

Then the speakers had to brought into the house for final assembly. There are three steps up into the house from the garage, and I don't think I can do it with the drivers installed. Fully assembled they weigh 145 pounds.
The horn went right back on with the #10-14 Plastite screws and fender washers. The woofer screwed down with 10-32 Allen screws. And the back went on with more 10-32 screws, this time flat head. The flat head screws look nice with finishing washers. All of the back hardware should be black, but for now it's silver.

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[Don C]

This is what they look like now. Sorry that the indoor pictures are not good.

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I'm very happy that this is all finished and paying off. They sound fantastic. Just the same as before really, but compared to the LE14s I'm noticing a little more sub-bass in the room. The tweeters are right at ear height. I'll do some measuring and check the port frequency later, but for now I'm just listening. Very happily.

[srm51555]

Nice work Don, thanks for taking us through the building process.

[Mr. Widget]

Nice work Don, thanks for taking us through the building process.
+1

Nicely done! The grilles look great, I'm surprised you didn't need to use a layer of perf to prevent the ribs from showing. I think I'd go with s darker fabric, but they look very nice.


Widget

[JeffW]

Those look great! Why the 1501FE instead of 2216? And it looks like your port tube ends are right up against the stuffing?

[grumpy]

...but for now I'm just listening. Very happily.

:thmbsup:
:cheers:

[Don C]

The grille cloth is actually touching the plastic of the horn. It doesn't show because the frame and horn match in profile so well. That tends to keep it flatter up top. The cloth does stretch to a slight curve vertically in front of the woofer, but its hard to notice. I installed it so that it stretches more side to side than top to bottom. Only because the frames are stronger side to side.
There is actually a gap between the end of the port tube and the fiberglass. Only about a half inch though. And the gap counts on my compressing the fiberglass a bit there. Is that a problem? I think that some of my factory JBLs have been like that too.
I used the 1501s because I bought them from the For sale area here on this forum prior to the 2216s becoming available. I think that they are just as good. I could have saved some weight with the 2216s, these are heavy.

[DavidF]

The grille cloth is actually touching the plastic of the horn. It doesn't show because the frame and horn match in profile so well. That tends to keep it flatter up top. The cloth does stretch to a slight curve vertically in front of the woofer, but its hard to notice. I installed it so that it stretches more side to side than top to bottom. Only because the frames are stronger side to side.
There is actually a gap between the end of the port tube and the fiberglass. Only about a half inch though. And the gap counts on my compressing the fiberglass a bit there. Is that a problem? I think that some of my factory JBLs have been like that too.
I used the 1501s because I bought them from the For sale area here on this forum prior to the 2216s becoming available. I think that they are just as good. I could have saved some weight with the 2216s, these are heavy.


http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=76604&d=1492411886



Jeez. look at how that all came together. Isn't it fun as all hell to sit back, look at this result, and say "yeah, I did that?" Well done.

[Don C]

I look at that picture and see the knot hole in the wood that shows through the cloth, and wonder why I foolishly selected that particular piece of wood to go on top. I guess it never occurred to me that it would show through the cloth, but there it is, plain as day. If I do change the cloth color I'll fill that hole while I'm at it.
Thanks for the kind comment though. I have been staring at them a lot, and often I'm very pleased.

[pos]

Wow! :coolness:
The integral grill frame is a very nice touch and fits perfectly.
I'd get them off the floor a bit, but I can see how this form factor can be appealing for consumer hifi.
I bet JBL is watching :D

[Earl K]

Beautiful work Don / love that grill!

:)

[cooky1257]

Nice work!

[Don C]

The emblem is small, but it seems to me that it makes a a big difference.

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[hsosdrum]

Just beautiful, Don! Thanks so much for documenting the build and sharing it with us.

[JuniorJBL]

Very nicely done Don!!

I really like the light color grill cloth myself!!

Maybe you could take the cloth off of the area with the knot and bondo/sand wood putty it. :dont-know:

BTW I bet the JBL emblem made it sound just a tad bit better!! :D

Congrats on a job well done!! ;)

[JeffW]

The emblem is small, but it seems to me that it makes a a big difference.

76639

The emblem gives it that authentic look, or something like that. I really like the way the fabric on top of the grill interacts with the top of the speaker and the side trim, nice contrast.

[Don C]

Thanks to everyone for the nice comments.
I'm looking at some mellotone brown cloth for a possible change.
I'm also playing around with external control circuits for the Blu-160. Super sensitive speakers like these tend to exaggerate the differences between different recordings, and I'm finding that it would help to have a bass level adjustment handy for those times when one recording sounds bass heavy, and the next disc is sounding weak in that department. A simple pot linked to a equalizer slider works, but is way too sensitive. What I need is a network of resistors on a control port that allows a smaller range of adjustment. Maybe plus or minus 3 db with a full turn of the knob. I'm working on that. One tip for those using Audio Architect. Version 2.0 is buggy. it will screw up your saved parametric EQ settings. I'd suggest to hold off on the upgrade until they fix it.

[grumpy]

Thanks for the AA info. Is Motion Control (on phone or tablet) an option?

here's a fun read (more of a loudness compensation, but could be modified)
http://harman-hsp-web-assets.s3.amazonaws.com/site_elements/executables/156_1364847298/creating-a-bass-lift-volume-control_original.pdf

[Don C]

I don't want to mess with the ipad app, because it would take too many steps to get the adjustment done, and then to get it undone afterwards. Anyway, I don't have an ipad. What I really want is one big knob or slider, right next to the main volume control, that I can know that state of just by looking. And get back to the starting point easily. That's why I don't want to do it in the HT processor either, I can't see where it is set easily, and would too often forget to return it to the default when a disc ends. I'm not usually playing music from a computer or storage, I'm changing discs in the Oppo BDP-103 player. So as long as I'm up, I can set the volume where I like it and tweak the bass a bit if needed before sitting back down. Easy.

[grumpy]

yup/understood.

Was mostly thinking you could run your existing pot as a control for the "noise generator" level
and then you'd have programmable control over range and linearity.

[sebackman]

Hi Jeff,

What filter settings did you finally use?

Kind regards
//Rob

[JeffW]

Hi Jeff,

What filter settings did you finally use?

Kind regards
//Rob

I think you meant to address Don C, I just reposted a pic of his speaker.